System and method for displaying runway landing information

ABSTRACT

A system and method are disclosed for indicating to an aircrew of an aircraft a normalized runway icon to ensure visualization of a predicted touchdown point, runway length, stopping distance, energy state marking, and threat conditions, where normalization is referenced to typically available length for landing. Indications of present aircraft locations relative to the icons as well as alerts when thresholds are exceeded are provided.

TECHNICAL FIELD

The present invention generally relates to a system for improving apilot's ability to complete a landing on a runway, and more particularlyto a system for displaying information to support a pilot's ability tofly the landing within desired parameters.

BACKGROUND

The approach to landing and touch down on the runway of an aircraft canbe a challenging task. To perform the landing properly, the aircraftapproaches the runway within an envelope of attitude, course, speed, andrate of descent limits. The course limits include, for example, bothlateral limits and glide slope limits. An approach outside of thisenvelope can result in an undesirable positioning of the aircraft withrespect to the runway.

When using a typical navigation map display to indicate approach landingstate, depending on the current display scale settings and phase ofapproach, the runway icon can very small and not suitable to display therelevant landing state information such predicted touch down point andthe predicted stopping point. As such, an iconized, dedicated runwaydisplay for indicating current landing state is best suitable for timelyand unambiguous information to flight crews.

Aircraft must be in correct configurations or energy state to completean effective landing. Clear and unambiguous information to flight crewsabout the present and predicted energy state are critical for flightcrews to make adjustment or decisions. Integration of this type ofinformation into traditional moving map displays has several draw backs:(1) In aircraft centered display mode typically used for final approachsegment, the runway symbol could be very small and cannot provide clearindication of the energy state information; (2) When using a moving mapdisplay, the airport and runway objects are typically shown to scale inorder to accommodate other necessary navigation and traffic objects onthe map. The scaling necessary for a moving map can also make the properdisplay of energy state information difficult to visualize for flightcrews during the critical time period.

Accordingly, it is desirable to provide a system and method forimproving the ability to fly stabilized landings including displayinginformation supporting a pilot's ability to fly the landings.Furthermore, other desirable features and characteristics of theexemplary embodiments will become apparent from the subsequent detaileddescription and the appended claims, taken in conjunction with theaccompanying drawings and the foregoing technical field and background.

BRIEF SUMMARY

A system and method are provided for displaying information allowing apilot to fly a stabilized approach to landing.

In an exemplary embodiment, a system for assisting a pilot of anaircraft to perform a stable landing, the system comprising a processorconfigured to determine an aircraft energy state of the aircraft; and adisplay responsive to the processor and configured to display a firstsymbol resembling a runway; display a second symbol indicating a lengthof the runway or runway length remaining; display a third symbolassociated with the first symbol indicating where the aircraft wouldtouch down when landing at the aircraft energy state determined by theprocessor; display a fourth symbol having a first format and associatedwith the first symbol indicating where the aircraft would be able tostop based on the aircraft energy state and a assumed brakingperformance; and if the aircraft is on the ground, display a fifthsymbol associated with the first symbol indicating the current locationof the aircraft on the runway; and display a sixth symbol associatedwith the first symbol indicating where the aircraft would be able tostop based on the aircraft energy state and current braking performance.

In another exemplary embodiment, a system for assisting a pilot of anaircraft to perform a stable landing, the system comprising a databaseconfigured to store information about a runway including a lengththereof; a processor coupled to the database and configured to determinean aircraft energy state of the aircraft; determine a position of theaircraft in relation to the runway; determine a stopping distance of theaircraft when landing on the runway based on the aircraft energy stateand a assumed braking performance; determine a stopping distance of theaircraft when landing on the runway based on the aircraft energy stateand current braking performance; and a display responsive to theprocessor and configured to display a first symbol resembling therunway; display a second symbol indicating the length of the runway orrunway length remaining; display a third symbol associated with thefirst symbol indicating where the aircraft would touch down when landingat the aircraft energy state determined by the processor; display afourth symbol having a first format and associated with the first symbolindicating where the aircraft would be able to stop based on theaircraft energy state and assumed braking performance; and display afifth symbol associated with the first symbol indicating the currentlocation of the aircraft on the runway; and display a sixth symbolassociated with the first symbol indicating where the aircraft would beable to stop based on the aircraft energy state and current brakingperformance.

In yet another exemplary embodiment, a method for assisting a pilot ofan aircraft to fly a stable landing, comprising determining via aprocessor an aircraft energy state of the aircraft; displaying via adisplay a first symbol resembling a runway; displaying via the display asecond symbol indicating a length of the runway or runway lengthremaining; displaying via the display a third symbol associated with thefirst symbol indicating where the aircraft would touch down when landingat the aircraft energy state; displaying via the display a fourth symbolhaving a first format and associated with the first symbol indicatingwhere the aircraft would be able to stop based on the aircraft energystate and assumed braking performance; displaying via the display afifth symbol associated with the first symbol indicating the currentlocation of the aircraft on the runway; and displaying via the display asixth symbol associated with the first symbol indicating where theaircraft would be able to stop based on the aircraft energy state andcurrent braking performance.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will hereinafter be described in conjunction withthe following drawing figures, wherein like numerals denote likeelements, and

FIG. 1 is a block diagram of an aircraft display system for generatingimages in accordance with exemplary embodiments;

FIGS. 2-5 are exemplary display screens presented to the crew of theaircraft in accordance with an exemplary embodiment;

FIG. 6 a flow diagram of an exemplary method suitable for use with thedisplay system of FIG. 1 in accordance with the exemplary embodiments.

During the course of this description, like numbers may be used toidentify like elements according to the different figures thatillustrate the various exemplary embodiments.

DETAILED DESCRIPTION

The following detailed description is merely illustrative in nature andis not intended to limit the embodiments of the subject matter or theapplication and uses of such embodiments. Any implementation describedherein as exemplary is not necessarily to be construed as preferred oradvantageous over other implementations. Furthermore, there is nointention to be bound by any expressed or implied theory presented inthe preceding technical field, background, brief summary, or thefollowing detailed description.

Those of skill in the art will appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection whir the embodiments disclosed herein may be implemented aselectronic hardware, computer software, or combinations of both. Some ofthe embodiments and implementations are described above in terms offunctional and/or logical block components (or modules) and variousprocessing steps. However, it should be appreciated that such blockcomponents (or modules) may be realized by any number of hardware,software, and/or firmware components configured to perform the specifiedfunctions. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,and steps have been described above generally in terms of theirfunctionality. Whether such functionality is implemented as hardware orsoftware depends upon the particular application and design constraintsimposed on the overall system. Skilled artisans may implement thedescribed functionality in varying ways for each particular application,but such implementation decisions should not be interpreted as causing adeparture from the scope of the present invention. For example, anembodiment of a system or a component may employ various integratedcircuit components, e.g., memory elements, digital signal processingelements, logic elements, look-up tables, or the like, which may carryout a variety of functions under the control of one or moremicroprocessors or other control devices. In addition, those skilled inthe art will appreciate that embodiments described herein are merelyexemplary implementations.

The various illustrative logical blocks, modules, and circuits describedin connection with the embodiments disclosed herein may be implementedor performed with a general purpose processor, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a. DSP core, or any other suchconfiguration. The word “exemplary” is used exclusively herein to mean“serving as an example, instance, or illustration.” Any embodimentdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other embodiments. Any of the abovedevices are exemplary, non-limiting examples of a computer readablestorage medium.

The steps of a method or algorithm described in connection with theembodiments disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such the processorcan read information from, and write information to, the storage medium.In the alternative, the storage medium may be integral to the processor.The processor and the storage medium may reside in an ASIC. The ASIC mayreside in a user terminal. In the alternative, the processor and thestorage medium may reside as discrete components in a user terminal. Anyof the above devices are exemplary, non-limiting examples of a computerreadable storage medium

In this document, relational terms such as first and second, and thelike may be used solely to distinguish one entity or action from anotherentity or action without necessarily requiring or implying any actualsuch relationship or order between such entities or actions. Numericalordinals such as “first,” “second,” “third,” etc. simply denotedifferent singles of a plurality and do not imply any order or sequenceunless specifically defined by the claim language. The sequence of thetext in any of the claims does not imply that process steps must beperformed in a temporal or logical order according to such sequenceunless it is specifically defined by the language of the claim. Theprocess steps may be interchanged in any order without departing fromthe scope of the invention as long as such an interchange does notcontradict the claim language and is not logically nonsensical.

Although embodiments described herein are specific to aircraft displaysystems, it should be recognized that principles of the inventivesubject matter may be applied to other vehicle display systems.

For the sake of brevity, conventional techniques related to graphics andimage processing, navigation, flight planning, aircraft controls,aircraft data communication systems, and other functional aspects ofcertain systems and subsystems (and the individual operating componentsthereof) may not be described in detail herein. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in an embodiment of the subject matter.

The following description refers to elements or nodes or features being“coupled” together. As used herein, unless expressly stated otherwise,“coupled” means that one element/node/feature is directly or indirectlyjoined to (or directly or indirectly communicates with) anotherelement/node/feature, and not necessarily mechanically. Thus, althoughthe drawings may depict one exemplary arrangement of elements,additional intervening elements, devices, features, or components may bepresent in an embodiment of the depicted subject matter. In addition,certain terminology may also be used in the following description forthe purpose of reference only, and thus are not intended to be limiting.

Alternate embodiments of the present invention to those described belowmay utilize whatever navigation system signals are available, forexample a ground based navigational system, a GPS navigation aid, aflight management system, and an inertial navigation system, todynamically calibrate and determine a precise course.

Some applications may require more than one monitor, for example, a headdown display screen, to accomplish the mission. These monitors mayinclude a two dimensional moving map display and a three dimensionalperspective display. A moving map display may include a top-down view ofthe aircraft, the flight plan, and the surrounding environment. Varioussymbols are utilized to denote navigational cues (e.g., waypointsymbols, line segments interconnecting the waypoint symbols, rangerings) and nearby environmental features (e.g., terrain, weatherconditions, political boundaries).

In accordance with the exemplary embodiments, a system and method aredescribed for indicating to an aircrew (1) display elements thatprovides awareness of the ability to complete a landing withinparameters based on the differences between current energy state anddesired energy state. (2) A dedicated iconized display representing therunway environment is used to place relevant approach state information.More specifically, an icon and symbology based landing runwayenvironment may be displayed on a primary flight display (PFD), in adedicated window on a multi-function display (MFD), or an electronicflight bag (EFB). The icon may include the following elements: (1) Anormalized runway icon to ensure visualization of distance marking,energy state marking, and threat conditions, where normalization isreferenced to typically available length for landing; (2) energy cues orsymbology relative to the normalized icons with the indications ofdistances, markings, and threat conditions; (3) indications of presentaircraft locations relative to the icons; (4) dynamic format change andlayering of the energy cues. For example, if the predicted touch downpoint is too far down the runway, the icon for the touchdown point willchange color and size, and is brought to the top layer; (5) coordinatedcaution and/or warning messages to the energy state icons. Messages suchas short runway may be displayed in addition to a stopping distancesymbol. An aural annunciation may also accompany the visual cautionand/or warning message.

The 2D icon runway display becomes available when in final approachconfigurations. The dedicated icon display can be fade onto a dedicatedarea of PFD or a dedicated window within a MFD or EFB displays in orderto show the relevant information for landing and take-off conditions.When a warning condition is issued, for example, GO AROUND caused byunstable approach conditions, both 2D runway borders and predictedstopping point symbology will change format, for example, become red, tobring attention to flight crews of such conditions associated with theapproach runway. In some situations, certain symbology such asindication for increased or maximum braking efforts and decelerationindications may be brought to the top of the displayed elements withchanging colors to indicate the required actions.

Referring to FIG. 1, an exemplary flight deck display system 100 isdepicted and will be described. The system 100 includes a user interface102, a processor 104, one or more terrain databases 106, one or morenavigation databases 108, various sensors 112, various external datasources 114, and a display device 116. The user interface 102 is inoperable communication with the processor 104 and is configured toreceive input from a user 109 (e.g., a pilot) and, in response to theuser input, supply command signals to the processor 104. The userinterface 102 may be any one, or combination, of various known userinterface devices including, but not limited to, a cursor control device(CCD) (not shown), such as a mouse, a trackball, or joystick, and/or akeyboard, one or more buttons, switches, or knobs. In the depictedembodiment, the user interface 102 includes a CCD and a keyboard (notshown). The user 109 uses the CCD to, among other things, move a cursorsymbol on the display screen (see FIG. 2), and may use the keyboard to,among other things, input textual data. It should be understood thatseveral of the blocks described as part of the flight deck displaysystem 100 are optional and not required for the exemplary embodiments,including the input device 102, the terrain database 106, the navigationdatabase 108, and sensors 112, for example.

The processor 104 may be any one of numerous known general-purposemicroprocessors or an application specific processor that operates inresponse to program instructions. In the depicted embodiment, theprocessor 104 includes on-board RAM (random access memory) 103, andon-board ROM (read only memory) 105. The program instructions thatcontrol the processor 104 may be stored in either or both the RAM 103and the ROM 105. For example, the operating system software may bestored in the ROM 105, whereas various operating mode software routinesand various operational parameters may be stored in the RAM 103. It willbe appreciated that this is merely exemplary of one scheme for storingoperating system software and software routines, and that various otherstorage schemes may be implemented. It will also be appreciated that theprocessor 104 may be implemented using various other circuits, not justa programmable processor. For example, digital logic circuits and analogsignal processing circuits could also be used.

No matter how the processor 104 is specifically implemented, it is inoperable communication with the terrain databases 106, the navigationdatabases 108, and the display device 116, and is coupled to receivevarious types of inertial data from the various sensors 112, and variousother avionics-related data from the external data sources 114. Theprocessor 104 is configured, in response to the inertial data and theavionics-related data, to selectively retrieve terrain data from one ormore of the terrain databases 106 and navigation data from one or moreof the navigation databases 108, and to supply appropriate displaycommands to the display device 116. The display device 116, in responseto the display commands, selectively renders various types of textual,graphic, and/or iconic information. The preferred manner in which thetextual, graphic, and/or iconic information are rendered by the displaydevice 116 will be described in more detail further below. Before doingso, however, a brief description of the databases 106, 108, the sensors112, and the external data sources 114, at least in the depictedembodiment, will be provided.

The terrain databases 106 include various types of data representativeof the terrain over which the aircraft is flying, and the navigationdatabases 108 include various types of navigation-related data. Thesenavigation-related data include various flight plan related data suchas, for example, waypoints, distances between waypoints, headingsbetween waypoints, data related to different airports, navigationalaids, obstructions, special use airspace, political boundaries,communication frequencies, and aircraft approach information. It will beappreciated that, although the terrain databases 106 and the navigationdatabases 108 are, for clarity and convenience, shown as being storedseparate from the processor 104, all or portions of either or both ofthese databases 106, 108 could be loaded into the RAM 103, or integrallyformed as part of the processor 104, and/or RAM 103, and/or ROM 105. Theterrain databases 106 and navigation databases 108 could also be part ofa device or system that is physically separate from the system 100.

The sensors 112 may be implemented using various types of inertialsensors, systems, and or subsystems, now known or developed in thefuture, for supplying various types of inertial data. The inertial datamay also vary, but preferably include data representative of the stateof the aircraft such as, for example, aircraft speed, heading, altitude,and attitude. The number and type of external data sources 114 may alsovary. For example, the external systems (or subsystems) may include, forexample, a terrain avoidance and warning system (TAWS), a traffic andcollision avoidance system (TCAS), a runway awareness and advisorysystem (RAAS), a flight director, and a navigation computer, just toname a few. However, for ease of description and illustration, only aglobal position system (GPS) receiver 122 is depicted in FIG. 1, andwill now be briefly described.

The GPS receiver 122 is a multi-channel receiver, with each channeltuned to receive one or more of the GPS broadcast signals transmitted bythe constellation of GPS satellites (not illustrated) orbiting theearth. Each GPS satellite encircles the earth two times each day, andthe orbits are arranged so that at least four satellites are alwayswithin line of sight from almost anywhere on the earth. The GPS receiver122, upon receipt of the GPS broadcast signals from at least three, andpreferably four, or more of the GPS satellites, determines the distancebetween the GPS receiver 122 and the GPS satellites and the position ofthe GPS satellites. Based on these determinations, the GPS receiver 122,using a technique known as trilateration, determines, for example,aircraft position, groundspeed, and ground track angle. These data maybe supplied to the processor 104, which may determine aircraft glideslope deviation therefrom. Preferably, however, the GPS receiver 122 isconfigured to determine, and supply data representative of, aircraftglide slope deviation to the processor 104.

The display device 116, as noted above, in response to display commandssupplied from the processor 104, selectively renders various textual,graphic, and/or iconic information, and thereby supply visual feedbackto the user 109. It will be appreciated that the display device 116 maybe implemented using any one of numerous known display devices suitablefor rendering textual, graphic, and/or iconic information in a formatviewable by the user 109. Non-limiting examples of such display devicesinclude various cathode ray tube (CRT) displays, and various flat paneldisplays such as various types of LCD (liquid crystal display) and TFT(thin film transistor) displays. The display device 116 may additionallybe implemented as a panel mounted display, a HUD (head-up display)projection, or any one of numerous known technologies. It isadditionally noted that the display device 116 may be configured as anyone of numerous types of aircraft flight deck displays. For example, itmay be configured as a multi-function display, a horizontal situationindicator, or a vertical situation indicator, just to name a few. In thedepicted embodiment, however, the display device 116 is configured as aprimary flight display (PFD).

In operation, the display system 100 is also configured to process thecurrent flight status data for the host aircraft 206. In this regard,the sources 106, 108, 112, 114 of flight status data generate, measure,and/or provide different types of data related to the operational statusof the host aircraft 206, the environment in which the host aircraft 206is operating, flight parameters, and the like. In practice, the sources106, 108, 112, 114 of flight status data may be realized using linereplaceable units (LRUs), transducers, accelerometers, instruments,sensors, and other well-known devices. The data provided by the sources106, 108, 112, 114 of flight status data may include, withoutlimitation: airspeed data; groundspeed data; altitude data; attitudedata, including pitch data and roll data; yaw data; geographic positiondata, such as GPS data; time/date information; heading information;weather information; flight path data; track data; radar altitude data;geometric altitude data; wind speed data; wind direction data; etc. Thedisplay system 100 is suitably designed to process data obtained fromthe sources 106, 108, 112, 114 of flight status data in the mannerdescribed in more detail herein. In particular, the display system 100can use the flight status data of the host aircraft when rendering theITP display.

It should be understood that FIG. 1 is a simplified representation of adisplay system 100 for purposes of explanation and ease of description,and FIG. 1 is not intended to limit the application or scope of thesubject matter in any way. In practice, the display system 100 and/oraircraft will include numerous other devices and components forproviding additional functions and features, as will be appreciated inthe art.

Referring to FIG. 2, textual, graphical, and/or iconic informationrendered by the display device 116, in response to appropriate displaycommands from the processor 104 is depicted, preferably as athree-dimensional perspective view, and is created from pre-storeddatabase information and flight management data, e.g., heading,altitude, and speed, superimposed on a synthetic rendering of terrain201 and objects such as a runway 202 and a taxiway 203. Morespecifically, the displayed representation 200 of an aircraft 206approach to landing includes, a compass 204, and various other dataincluding an altimeter 208, a barometric pressure setting indicator 210,a vertical feet-per-minute indicator 212, an airspeed indicator 214, aground speed indicator 216, and various other information known to thoseskilled in the art. A flight path marker 225 is typically a circle withhorizontal lines (representing wings) extending on both sides therefrom,a vertical line 227 (representing a rudder) extending upwards therefrom,and indicates where the plane is “aimed” during normal flight.Additional data (not shown) could also be displayed, and some of thoseindicators shown could be omitted.

In accordance with the exemplary embodiments, an aircraft energy stateis determined from a plurality of flight parameters including airspeed,groundspeed, altitude above the runway, distance to the runway, aircraftconfiguration, and engine power settings. The aircraft energy state isthen compared with a desired stable approach energy state. A calculationis then made for required rates of airspeed and vertical speedadjustments, based on the airframe parameters, in order to correct theaircraft energy state to that of the desired state. That requiredadjustment rates to various parameters are then converted into a desireddeceleration or acceleration indicator along the flight path directionas a first icon, e.g., the chevron 222. Flight crews can then adjustaircraft configurations, engine power setting, etc. such that theinstantaneous acceleration chevron 223 can be gradually overlapping withthe desired acceleration chevron 222. A target airspeed 221 is indicatedon the airspeed indicator 214, and optionally may also be displayeddigitally as numbers 224.

Furthermore, in accordance with the exemplary embodiments for landingoperations, a symbol 226 representing the runway 202 is displayed on thedisplay 200, having a symbol 228, e.g., a circle, representing where theaircraft would touchdown on the runway 202 if the current energy statewere maintained. The symbol 232 represents a desired touchdown point,and the number 234 at the end of the runway indicate the runway length.The symbol 236, e.g. a series of rectangles, indicates where theaircraft should be able to stop in view of the touchdown point 228,energy state of the aircraft, and an assumed braking performance.Assumed braking performance includes the assumed braking action applied,i.e., maximum manual braking or autobraking setting as well as theassumed runway surface conditions. In this descriptive example, thetouchdown symbol 228 is near the threshold 229, resulting in a distancesufficient to stop the plane on the runway 202. The format of the symbol236 preferably would be such, e.g., green, that would indicate thestopping distance is within a safety margin.

In the descriptive example of FIG. 3, the touchdown symbol 228 is beyondthe threshold 232, resulting in a reduced distance to stop the aircrafton the runway 202. The format of the symbol 236 preferably would besuch, e.g., yellow, that would indicate the stopping distance ismarginal.

Referring to FIG. 4, the touchdown symbol 228 is well beyond thethreshold 232, resulting in insufficient distance to stop the aircrafton the runway 202. The format of the symbol 236 preferably would besuch, e.g., red, which would indicate the stopping distance is notsufficient.

FIG. 5 depicts the symbology once the aircraft has touched down on therunway. Symbol 302 depicts the current position of the aircraft on therunway 304 and the number 306 at the end of the runway indicated thedistance remaining to the end of the runway. Symbol 308 indicates thepoint on the runway were the aircraft will stop based on the currentaircraft state and current aircraft stopping performance.

FIG. 6 is a flow chart that illustrates an exemplary embodiment of amethod 600 suitable for use with a flight deck display system 100.Method 600 represents one implementation of a method for displayingaircraft approaches or departures on an onboard display of a hostaircraft. The various tasks performed in connection with method 600 maybe performed by software, hardware, firmware, or any combinationthereof. For illustrative purposes, the following description of method600 may refer to elements mentioned above in connection with precedingFIGS. In practice, portions of method 600 may be performed by differentelements of the described system, e.g., a processor, a display element,or a data communication component. It should be appreciated that method600 may include any number of additional or alternative tasks, the tasksshown in FIG. 6 need not be performed in the illustrated order, andmethod 600 may be incorporated into a more comprehensive procedure ormethod having additional functionality not described in detail herein.Moreover, one or more of the tasks shown in FIG. 6 could be omitted froman embodiment of the method 600 as long as the intended overallfunctionality remains intact.

In accordance with the exemplary method of FIG. 6, a method 600 methodfor assisting a pilot of an aircraft to fly a stable landing includesdetermining 602 via a processor an aircraft energy state of theaircraft; displaying 604 via a display a first symbol resembling arunway; displaying 606 via the display a second symbol indicating alength of the runway or runway length remaining; displaying 608 via thedisplay a third symbol associated with the first symbol indicating wherethe aircraft would touch down when landing at the aircraft energy state;displaying 610 via the display a fourth symbol having a first format andassociated with the first symbol indicating where the aircraft would beable to stop based on the aircraft energy state and assumed brakingperformance; displaying 612 via the display a fifth symbol associatedwith the first symbol indicating the current location of the aircraft onthe runway; and displaying 614 via the display a sixth symbol associatedwith the first symbol indicating where the aircraft would be able tostop based on the aircraft energy state and current braking performance.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any element(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature or element of any or all the claims. As used herein, the terms“comprises,” “comprising,” or any other variation thereof, are intendedto cover a non-exclusive inclusion, such that a process, method,article, or apparatus that comprises a list of elements does not includeonly those elements but may include other elements not expressly listedor inherent to such process, method, article, or apparatus.

While at least one exemplary embodiment has been presented in theforegoing detailed description, it should be appreciated that a vastnumber of variations exist. It should also be appreciated that theexemplary embodiment or exemplary embodiments are only examples, and arenot intended to limit the scope, applicability, or configuration of theinvention in any way. Rather, the foregoing detailed description willprovide those skilled in the art with a convenient road map forimplementing an exemplary embodiment of the invention, it beingunderstood that various changes may be made in the function andarrangement of elements described in an exemplary embodiment withoutdeparting from the scope of the invention as set forth in the appendedclaims.

What is claimed is:
 1. A system for assisting a pilot of an aircraft toperform a stable landing, the system comprising: a processor configuredto: determine an aircraft energy state of the aircraft; and a displayresponsive to the processor and configured to: display a first symbolresembling a runway; display a second symbol indicating a length of therunway or runway length remaining; display a third symbol associatedwith the first symbol indicating where the aircraft would touch downwhen landing at the aircraft energy state determined by the processor;display a fourth symbol having a first format and associated with thefirst symbol indicating where the aircraft would be able to stop basedon the aircraft energy state and assumed braking performance; change thefourth symbol to a second format when the fourth symbol is at an end ofthe runway; and if the aircraft is on the ground, display a fifth symbolassociated with the first symbol indicating the current location of theaircraft on the runway; and display a sixth symbol associated with thefirst symbol indicating where the aircraft would be able to stop basedon the aircraft energy state and current braking performance.
 2. Thesystem of claim 1 wherein the processor is further configured to:consider an airspeed, altitude, and distance to the runway of theaircraft when determining the aircraft energy state.
 3. The system ofclaim 2 wherein the processor is further configured to: consider aconfiguration of the aircraft when determining the aircraft energystate.
 4. The system of claim 1 wherein the processor is furtherconfigured to: change the fourth symbol to a third format when theaircraft would be unable to stop by the end of the runway.
 5. The systemof claim 1 further comprising an audio device, wherein the processor isfurther configured to: command the audio device to provide an audioalert that the aircraft would be unable to stop by the end of therunway.
 6. The system of claim 1, wherein the processor is furtherconfigured to: determine which of the second, third, fourth, fifth, orsixth symbol is most critical to current aircraft operations, whereinthe second, third, fourth, fifth, or sixth symbols occupy layers of thedisplay; and wherein the display is further configured to: display themost critical symbol in the layer closest to the pilot.
 7. A system forassisting a pilot of an aircraft to perform a stable landing, the systemcomprising: a database configured to store information about a runwayincluding a length thereof; a processor coupled to the database andconfigured to: determine an aircraft energy state of the aircraft;determine a position of the aircraft in relation to the runway;determine a stopping distance of the aircraft when landing on the runwaybased on the aircraft energy state and assumed braking performance;determine a stopping distance of the aircraft when landing on the runwaybased on the aircraft energy state and current braking performance; anda display responsive to the processor and configured to: display a firstsymbol resembling the runway; display a second symbol indicating thelength of the runway or runway length remaining; display a third symbolassociated with the first symbol indicating where the aircraft wouldtouch down when landing at the aircraft energy state determined by theprocessor; display a fourth symbol having a first format and associatedwith the first symbol indicating where the aircraft would be able tostop based on the aircraft energy state and assumed braking performance;display a fifth symbol associated with the first symbol indicating thecurrent location of the aircraft on the runway; display a sixth symbolassociated with the first symbol indicating where the aircraft would beable to stop based on the aircraft energy state and current brakingperformance; and change the fourth symbol to a second format when thefourth symbol is at an end of the runway.
 8. The system of claim 7wherein the processor is further configured to: consider an airspeed,altitude, and distance to the runway of the aircraft when determiningthe aircraft energy state.
 9. The system of claim 8 wherein theprocessor is further configured to: consider a configuration of theaircraft when determining the aircraft energy state.
 10. The system ofclaim 7 wherein the processor is further configured to: change thefourth symbol to a third format when the aircraft would be unable tostop by the end of the runway.
 11. The system of claim 7 furthercomprising an audio device, wherein the processor is further configuredto: command the audio device to provide an audio alert that the aircraftwould be unable to stop by the end of the runway.
 12. A method forassisting a pilot of an aircraft to fly a stable landing, comprising:determining via a processor an aircraft energy state of the aircraft;displaying via a display a first symbol resembling a runway; displayingvia the display a second symbol indicating a length of the runway orrunway length remaining; displaying via the display a third symbolassociated with the first symbol indicating where the aircraft wouldtouch down when landing at the aircraft energy state; displaying via thedisplay a fourth symbol having a first format and associated with thefirst symbol indicating where the aircraft would be able to stop basedon the aircraft energy state and assumed braking performance; displayingvia the display a fifth symbol associated with the first symbolindicating the current location of the aircraft on the runway;displaying via the display a sixth symbol associated with the firstsymbol indicating where the aircraft would be able to stop based on theaircraft energy state and current braking performance; and changing viathe processor the fourth symbol to a second format when the fourthsymbol is at an end of the runway.
 13. The method of claim 12 furthercomprising: considering via the processor the airspeed, altitude, anddistance to the runway when determining the aircraft energy state. 14.The method of claim 13 further comprising: considering via the processorthe configuration of the aircraft when determining the aircraft energystate.
 15. The method of claim 12 further comprising: changing via theprocessor the fourth symbol to a third format when the aircraft would beunable to stop by the end of the runway.
 16. The method of claim 12further comprising: commanding via the processor an audio device toprovide an audio alert that an approach of the aircraft is unstableexceeds a threshold related to the stopping distance of the aircraft.17. The method of claim 12 further comprising: determining which of thesecond, third, fourth, fifth, or sixth symbol is most critical tocurrent aircraft operations, wherein the second, third, fourth, fifth,or sixth symbols occupy layers of the display; and displaying the mostcritical symbol in the layer closest to the pilot.